1. Field of the Invention
The present invention relates to a vibroisolating handle joint structure for a power tool such as a disc grinder.
2. Description of the Prior Art
Japanese Laid-Open Utility Model Publication No. 47-26382, published Nov. 25, 1972, discloses a powered hand tool such as a disc grinder having a vibroisolating handle joint structure which includes elastic members interposed between a power tool unit and a handle for preventing vibrations from being transmitted from the power tool unit to the hand of the user which grips the handle. Each of the elastic members is made of rubber or the like with two metallic plates fixed to opposite sides of the elastic member by means of screws. One of the metallic plates is fastened to the power tool unit whereas the other metallic plate is fastened to the handle, thus interconnecting the power tool unit and the handle.
Generally, electrically powered hand tools have tool casings and handles which are made of plastics, i.e., an electric insulator, for protecting the user from accidental electric shocks.
The metallic plates in the power tool disclosed in the above publication must also be insulated for safety. Therefore, the disclosed power tool is large in size and heavy in weight because of the insulation needed by the metallic plates, and hence cannot easily be handled in use. Another problem with the conventional power tool is that since the tool and the handle are joined to each other only by the elastic members, the bonding strength between the metallic plates and the elastic members has to be of a predetermined level or higher. It requires a costly, laborious, and time-consuming process to obtain the required bonding strength between the metallic plates and the elastic members.